While an energy problem has been serious, attention has been paid to renewable energy. However, since the renewable energy such as sunlight and wind power is fluctuated and unevenly distributed, transportation and storage as electric energy are difficult. For this reason, hydrogen is a strong candidate for the transportation and storage of the renewable energy. However, hydrogen is a gas at a normal temperature and a normal pressure and is not suitable for the transportation and storage.
Attention is paid to organic hydrides using hydrocarbons, such as cyclohexane, methyl cyclohexane, and decalin, which are used for transportation and storage of hydrogen. The organic hydrides are a liquid at a normal temperature and a normal pressure, and are easily handled. When the organic hydrides are electrochemically hydrogenated or dehydrogenated, the organic hydrides act as an energy carrier instead of hydrogen to enable storage and transportation.
In conventional production of organic hydrides such as methyl cyclohexane, hydrogen is produced by water electrolysis using renewable energy, and toluene is hydrogenated using a hydrogenation reactor to produce methyl cyclohexane. In an electro-synthesis method, a process can be simplified by direct hydrogenation.